Resin bottles, representatives of which are Oriented Polypropylene (OPP) bottles and Poly-Ethylene Terephthalate (PET) bottles, are used in various fields, such as beverages, foods, cosmetics, and so forth. Such a bottle is generally formed in a predetermined shape by biaxially stretch blow molding a resin preform by using a blow molding device. The resin preform has been formed in a bottomed tubular shape by, for example, injection molding.
One example of such a blow molding device is the one that uses a pressurized liquid, instead of pressurized air, as the pressurized fluid that is filled into the preform. In this case, by using a content liquid, such as a beverage, a cosmetic product, a pharmaceutical product, or the like, that is to be filled in a final product as the liquid, the process of filling the content liquid to the bottle may be omitted, and the production process and the configuration of the blow molding device may be simplified.
For example, Patent Literature 1 describes a blow molding device including a blow molding mold to which a preform, after heated to a temperature at which the preform is stretchable, is fitted, a blow nozzle that is fitted to as mouth tubular portion of the preform fitted, to the mold, a pressurized liquid supply unit configured to supply a pressurized liquid to the blow nozzle, and a stretching rod that is freely displaceable in upward and downward directions. By stretching the preform in the longitudinal (axial) direction by the stretching rod and by filling the pressurized liquid into the preform through the blow nozzle, the preform is stretched in the lateral (radial) direction into a shape conforming to a cavity of the mold.